A keyboard apparatus is commonly used for inputting data into a computer, and the keycaps above a keyboard are formed with various text and symbols thereon due to different characters in use from one country to another. There are many ways for forming the text and symbols on the keycaps. In some manufacturing processes, the keycaps need to be painted to provide for the appearance of various colors. When the keycaps are to be painted, the keycaps need to be fixed to a keycap painting jig for painting, baking, printing processes and the like, and then are mounted to a base plate of a keyboard.
In a conventional manner of fixing the keycaps to the painting jig, the painting jig are generally directly fixed to connecting structures on the bottom surface of the keycap, i.e. drop-like pivoting holes, which are used to be mounted to lifting mechanisms on the base plate of the keyboard. The painting jig is disposed with engagement structures to be directly engaged in the pivoting holes of the keycaps, achieving the purpose of fixing the keycaps to the painting jig. After the painting has been completed, the keycaps are removed from the painting jig.
However, repeated use of the painting jig for painting, baking, and the like often results in dimensional changes in the engagement structures for fixing the keycaps on the painting jig. If the keycaps are fixed to the painting jig for painting, after the keycaps are subjected to plugging and unplugging processes, the connection structures of the keycaps may be deformed, so that the keycaps cannot be securely mounted to the base plate of the keyboard. The strength at which the keycaps are bound to the keyboard is affected, and even the quality test of the keyboard may be affected.